Jose Antonio Arias Alvarez has previously discovered that inorganic salts of sulfurous acid (especially sodium bisulfite) are antihypertensive agents. See U.S. application, Ser. No. 75,423, filed Sept. 14, 1979, now U.S. Pat. No. 4,327,083 issued Apr. 27, 1982.
Sodium bisulfite (usually shown by formula to be NaHSO.sub.3) has heretofore been used for many commercial purposes, such as a preservative for prevention of the deterioration of liquid systems, such as food stuffs and of pharmaceutical solids, and has also been used medically both externally, such as for treatment of parasitic skin diseases, and internally such as for a gastrointestinal antiseptic. So far as now known, sodium bisulfite has never previously been used by man for the treatment of hypertension.
The solid sodium bisulfite of commerce reportedly consists chiefly of sodium metabisulfite, Na.sub.2 S.sub.2 O.sub.5, and sodium bisulfite, and, for purposes of this invention, such is believed to possess the same properties as (and to be equivalent to) sodium bisulfite when dissolved in aqueous solution.